Efficacy and safety of scheduled early endoscopic ultrasonography‐guided ethanol reinjection for patients with pancreatic neuroendocrine tumors: Prospective pilot study

Endoscopic ultrasonography (EUS)-guided ethanol injection was recently proposed for treatment of patients with small pancreatic neuroendocrine tumors (p-NET); however, tips on how to carry out safe and effective procedures are unclear. We launched a pilot study for scheduled early EUS-guided ethanol reinjection for small p-NET. Major eligibility criteria were presence of pathologically diagnosed grade (G) 1 or G2, tumor size ≤2 cm and being a poor or rejected candidate for surgery. For the treatment, we used a 25-gauge needle and pure ethanol. Contrast-enhanced computed tomography (CE-CT) was carried out on postoperative day 3, and if enhanced areas of the tumor were still apparent, an additional session was scheduled during the same hospitalization period. Primary endpoint was complete ablation rate at 1 month after treatment, and secondary endpoint was procedure-related adverse events. A total of five patients were treated. Median size of the tumor was 10 (range: 7-14) mm. Of the five patients, three underwent an additional session. Median volume of ethanol injection per session was 0.8 (range: 0.3-1.0) mL, and the total was 1.0 (0.9-1.8) mL. Complete ablation was achieved in four of the five tumors (80%) with no adverse events. During 1 year of follow up, none of the patients reported any procedure-related adverse events, and no recurrence of tumor. Scheduled early EUS-guided ethanol reinjection appears to be safe and effective for treating small p-NET (UMIN number: 000018834).